Pressure sensors must be built for use in a variety of environments. Often, the fluid of interest is not a “clean” fluid, but instead is in a harsh environment, which may contain foreign object debris. Pressure sensors for use in harsh environments must be designed to avoid destruction and clogging of the pressure sensing die used in such environments.
Traditionally, harsh environment pressure sensors used fluid separation membranes to separate the pressure sensing die from the measurement environment where the process fluid of interest was located. The fluid separation membrane, placed between the process fluid field and the sensing die, transfers the pressure of the process fluid to the pressure sensing die in the device. However, to contain isolation oil, these designs relied on expensive hermetically-sealed glassed-in pins to provide feedthrough of electrical signals. Traditional designs also created unwanted pockets in the path to the sensing die, clogging the pressure sensor with external, harsh environment fluid, and foreign objects within the pockets of the pressure sensor. The large coefficient of thermal expansion of the oil in conjunction with the compliance of the isolator created performance errors with pressure readings in such sensors. Additionally, the remote distance of the pressure sensing die itself from the process fluid, due to the space of the oil-filled isolator, created performance errors and delayed response with pressure readings.